Long Tailed Comet SWAN
7.05.2020

Blowing in the solar wind the spectacular ion tail of Comet SWAN (C/2020 F8) extends far across this 10 degree wide telephoto field of view. Captured on May 2 its greenish coma was about 6 light-minutes from Earth. The pretty background starfield lies near the border of the constellations Cetus and Aquarius.

Mercury: A Cratered Inferno
12.09.1996

Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways.

Saturns Iapetus: Moon with a Strange Surface
31.01.2005

What has happened to Saturn's moon Iapetus? A strange ridge crosses the moon near the equator, visible near the bottom of the above image, making Iapetus appear similar to the pit of a peach. Half of Iapetus is so dark that it can nearly disappear when viewed from Earth.

The First Explorer
5.02.1999

The first US spacecraft was Explorer 1. The cylindrical 30 pound satellite was launched (above) as the fourth stage of a Jupiter-C rocket (a modified US Army Redstone ballistic missile) and achieved orbit on January 31, 1958.

Tychos Supernova Remnant in X ray
6.03.1999

How often do stars explode? By looking at external galaxies, astronomers can guess that these events, known as a supernovae, should occur about once every 30 years in a typical spiral galaxy like our MilkyWay.

Liquid Lakes on Saturns Titan
6.02.2007

Why would some regions on Titan reflect very little radar? The leading explanation is that these regions are lakes, possibly composed of liquid methane. The above image is a false-color synthetic radar map of a northern region of Titan taken during a flyby of the cloudy moon by the robotic Cassini spacecraft last July.

Mimas: Small Moon with a Big Crater
17.05.2009

Whatever hit Mimas nearly destroyed it. What remains is one of the largest impact craters on one of Saturn's smallest moons. The crater, named Herschel after the 1789 discoverer of Mimas, Sir William Herschel, spans about 130 kilometers and is pictured above.

Comet ISON Before and After
29.11.2013

Sungrazing Comet ISON reached perihelion, its closest approach to the Sun, yesterday, November 28, at 18:45 UT. The comet passed just over 1 million kilometers above the solar surface, a distance less than the diameter of the Sun.

The Great Crater Hokusai
17.04.2015

One of the largest young craters on Mercury, 114 kilometer (71 mile) diameter Hokusai crater's bright rays are known to extend across much of the planet. But this mosaic of oblique views focuses...

Plutos Sputnik Planum
21.11.2016

Is there an ocean below Sputnik Planum on Pluto? The unusually smooth 1000-km wide golden expanse, visible in the featured image from New Horizons, appears segmented into convection cells. But how was this region created?